Comparison of carbon dioxide emissions for two landfill capping layers

Geosynthetics are commonly employed in landfill applications to provide containment in the capping layer, also referred to as a cover system. This paper presents a case study that compared the carbon dioxide emissions produced from a compacted clay landfill cap with one incorporating geosynthetics. The lifecycle analysis boundaries set for the case study were cradle to end-of-construction, and included all processes from sourcing of materials through to the end-of-construction. As-built data provided by contractors and manufacturers were used to calculate the carbon footprint of each solution and the comparison showed the geosynthetic solution to be more sustainable. However, deficiencies in standard database values revealed inconsistencies and a value for the embodied carbon of clay was calculated using primary data. The embodied carbon value calculated from the primary data was much lower than the one initially employed and hence made the clay solution more sustainable where materials were locally available.